/*第一种方法：*/
    String path = "file:///android_asset/文件名";

/*第二种方法：*/
    InputStream abpath = getClass().getResourceAsStream("/assets/文件名");

/*若要想要转换成String类型*/
	String path = new String(InputStreamToByte(abpath ));
    private byte[] InputStreamToByte(InputStream is) throws IOException {
        ByteArrayOutputStream bytestream = new ByteArrayOutputStream();
        int ch;
        while ((ch = is.read()) != -1) {
            bytestream.write(ch);
        }
        byte imgdata[] = bytestream.toByteArray();
        bytestream.close();
        return imgdata;
    }